lock sizes, use blockgroups

1 files changed, 14 insertions, 4 deletions

diff --git a/pkg/btrfs/btrfsvol/devext.go b/pkg/btrfs/btrfsvol/devext.go
index 736d39b..8a69c7e 100644
--- a/pkg/btrfs/btrfsvol/devext.go
+++ b/pkg/btrfs/btrfsvol/devext.go
@@ -8,10 +8,11 @@ import (
 
 // physical => logical
 type devextMapping struct {
-	PAddr PhysicalAddr
-	LAddr LogicalAddr
-	Size  AddrDelta
-	Flags *BlockGroupFlags
+	PAddr      PhysicalAddr
+	LAddr      LogicalAddr
+	Size       AddrDelta
+	SizeLocked bool
+	Flags      *BlockGroupFlags
 }
 
 // return -1 if 'a' is wholly to the left of 'b'
@@ -50,6 +51,15 @@ func (a devextMapping) union(rest ...devextMapping) (devextMapping, error) {
 		PAddr: beg,
 		Size:  end.Sub(beg),
 	}
+	for _, ext := range exts {
+		if ext.SizeLocked {
+			ret.SizeLocked = true
+			if ret.Size != ext.Size {
+				return devextMapping{}, fmt.Errorf("member devext has locked size=%v, but union would have size=%v",
+					ext.Size, ret.Size)
+			}
+		}
+	}
 	// figure out the logical range (.LAddr)
 	first := true
 	for _, ext := range exts {